Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

A (Atmospheric and Hydrospheric Sciences ) » A-CG Complex & General

[A-CG39] Biogeochemical cycles in Land Ecosystem

Tue. May 28, 2019 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Tomomichi Kato(Research Faculty of Agriculture, Hokkaido University), Kazuhito Ichii(Chiba University), Takeshi Ise(FSERC, Kyoto University), Munemasa Teramoto(National Institute for Environmental Studies)

[ACG39-P01] Long-term warming effect on heterotrophic respiration in a beech forest on Mount Naeba

*Munemasa Teramoto1, Naishen Liang1, Masaaki Naramoto2, Jiye Zeng1, Zhao Xin1, Hajime Tomimastu1 (1.Center for Global Environmental Research, National Institute for Environmental Studies, 2.Faculty of Agriculture, Shizuoka University)

Keywords:soil organic carbon, global warming, heterotrophic respiration, chamber, Asian monsoon

Soil respiration is the second largest carbon flux in terrestrial ecosystems and the global soil respiration is estimated to be 98 GtC yr-1. Soil respiration consists of root respiration and heterotrophic respiration (Rh), and Rh contributes more than half of the soil respiration. It is commonly observed that Rh exponentially increases with temperature. Therefore, a small increase of temperature can result in a remarkable enhancement of Rh, indicating that it is an important positive feedback factor to accelerate global warming under a warmer environment. However, the long-term warming effect on Rh is not well understood especially in the humid Asian monsoon region.

To examine the long-term response of Rh to global warming in Asian monsoon forests, we set a multi-channel automated chamber measurement system in a beech forest on Mount Naeba in July 2007. We prepared 10 trenched chambers (90 cm × 90 cm × 50 cm) to continuously measure Rh. Half of those trenched chambers were artificially warmed by infrared heaters 1.6 m above the soil surface (+2.5ºC), and the influence of soil warming on Rh was examined by comparing control plots and warming plots. Measurements were conducted mainly during growing season from June to October.

Even though there was a large inter-annual variation, enhancement of Rh by soil warming was confirmed in all 8 years measurements. Soil temperature was the primary factor for the seasonal variation of Rh. The influence of soil moisture on seasonal variation of Rh was relatively small.